Hi, Last week I bought a 2009 Focus Zetec S (1.8), 34,000 miles and full Ford service history (I just had the 3rd Service/37,000 mile service done on Friday).

Sometimes on start up when cold (if I don't give the car any revs at all) it idles around 500rpm. Hit the accelerator and the car will rev to about 1,800/2,000rpm and then drop to a comfortable 800rpm. It doesn't happen all the time and if it does its only on start up after a period of standing (couple of hours). Is this the Idle Control Valve (I'm not massively techy but reading up on here it sounds similar its just I've not seen anyone mention that the issue is only on start up)???.

The car came with 1 month warranty from the garage which I bought it from.

Yes it's Petrol. It usually idles around 800rpm when warm but occasionally on start it's sitting at 500rpm which causes it to feel like it's about to stall (not surprisingly). The thing that throws me is that it doesn't happen all the time and only ever happens on start-up

sounds to me like its fuel starvation. Normally revs are about 680 on idle, either your idle control valve needs a clean or swapping, or perhaps your not getting fuel efficiently causing the stammers...